Combinaton of Multiple Stereo Systems

Parallel use of stereo systems

Apply­ing mul­ti­ple sys­tems enables the enlarge­ment of the FOV and/or to increase the spa­tial res­o­lu­tion. Dif­fer­ent meth­ods are avail­able for com­bin­ing their results and coor­di­nates by the VIC soft­ware. A unique method with high­er accu­ra­cy than  onven­tion­al ones enables to com­bine any obser­va­tion direc­tions — in this exam­ple, side by side sys­tems (right image) — even with­out an over­lap of the FOV, which is required for the con­ven­tion­al stitch­ing method. This dou­bles the spa­tial resolution.



Flexibility in combination of multiple systems

Here, opposed sys­tems oper­ate at dif­fer­ent field of view ranges. Click for the high-res­o­lu­tion mea­sure­ment of prin­ci­pal strain ε1 and ε2 tak­en from the backside.








Bending Test

The video exam­ple shows a four point bend­ing test set­up for a met­al beam with drilled holes (side view). The beam sur­face is mea­sured by a VIC-3D Pro­fes­sion­al stereo sys­tem from below via a sur­face coat­ed mir­ror. The mea­sured prin­ci­pal strain are pro­ject­ed on the mir­rored image of the sam­ple sur­face. Mea­sure­ment of 9/2023, Uni­ver­si­ty of Lübeck.

NIST (National Institute of Standards and Technology) using Vic-3D for digital image correlation (DIC)

NIST is using the Vic-3D dig­i­tal image cor­re­la­tion (DIC) sys­tem to ana­lyze stress in bridges. By using DIC, they try to under­stand the impact of stress­es and strains on the met­al con­nec­tors of bridges in order to avoid dam­age or failure.

NIST is pre-strain­ing a wide plate with dig­i­tal image cor­re­la­tion (DIC) to deter­mine the small-scale spec­i­men sec­tion­ing plan:

NIST is con­duct­ing a CWP test with dig­i­tal image cor­re­la­tion (DIC) to deter­mine local and remote strains used to deter­mine the Ten­sile Strain Capac­i­ty of a flawed pipe girth-weld:

NIST is mak­ing an SE(T) test with dig­i­tal image cor­re­la­tion (DIC) show­ing the asym­met­ric strain gra­di­ent of a spec­i­men notched in the heat-affect­ed zone:

DIC measurements on structural concrete

The ETH Zürich — one of our long­stand­ing cus­tomers — pro­vides on the fol­low­ing web­site their research project. They ana­lyze the accu­ra­cy of dig­i­tal image cor­re­la­tion with­in the scope of rein­forced con­crete. Prof. Dr. Wal­ter Kauf­mann and Dr. Jaime Mata Fal­cón are mem­bers of the project.


Full-field strain mea­sure­ment in rebar tension 

test: fail­ure phase.

Strain Gauge Comparison

In this exam­ple a Vic-3D mea­sure­ment with 5MP CMOS Cam­era was per­formed. The acryl spec­i­men is fixed in a ten­sile test­ing machine. A strain gauge is attached at the back in com­bi­na­tion with a SCAD 500 strain gauge ampli­fi­er. The out­put of the SCAD 500 was con­nect­ed to the DAQ of the DIC sys­tem. The strain results are record­ed par­al­lel with the Vic-3D mea­sure­ment and plot­ted in a dia­gram. The cam­era type is equipped with Sony 5Mpx Pregius sen­sor, 75 fps.

Strain Gauge Comparison-1  Strain Gauge Comparison-1a

Image 1: Vic-3D mea­sure­ment of the acryl specimen


Strain Gauge Comparison-2









Image 2: Com­par­i­son of strain gauge data (red curve) and DIC Strain data (black curve)


The Vic-3D data match near­ly per­fect with the strain gauge data. Even at low strains the dif­fer­ence is less than 25 micro strain.

NDT of Carbon-NOMEX (honeycomb core) composite: Dynamic loading on a large yacht hull

Marine NDE (Spain) used the tech­ni­cal advan­tages of our Shearog­ra­phy-Sys­tem espe­cial­ly in com­bi­na­tion with the dynam­ic exci­ta­tion for non-destruc­tive exam­i­na­tion (NDE) of large areas such as com­plete yacht hulls (see image below). The hull with a lenghts of 30,5m was a car­bon-fir­ber-com­pos­ite and part of high per­for­mance sail­ing yacht in build. Because of the full-field method (100% of the inspect­ed area is exam­ined), the test­ing of the entire hull required only 240 shots, in three workdays.


The yacht hull con­sists of a sand­wich con­struc­tion, where are in par­tic­u­lar used hon­ey­comb cores (NOMEX).

Marine NDT1Marine NDT2







On the left — A shearo­gram of a detect­ed bond­ing defect (in red oval). The yel­low X marks the loca­tion of the core sam­ple shown at the right. The destruc­tive test con­firms the shearo­gram’s indi­ca­tion that there is a sig­nif­i­cant nev­er-bond between the hon­ey­comb core mate­r­i­al and the film adhe­sive in this area.


Deformation Measurement

The fol­low­ing video clips show a defor­ma­tion- or strain-mea­sure­ment of a met­al spring ele­ment, mea­sured by using Vic-3D.

The first defor­ma­tion mea­sure­ment would be made in the X direction.


The sec­ond defor­ma­tion mea­sure­ment would be made in the Y direction.


The third defor­ma­tion mea­sure­ment would be made in the Z direction.


In the last case you see the result of the strain measurement.